<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>

</body>
<script type="text/javascript">
var year = prompt("请输入年份：");

if(year%4==0&&year%100!=0||year%400==0){
    document.write("是闰年");
}else{
　　 document.write("不是闰年");
　　}
</script>
</html>